Socialite-turned-fashion designer Nicole Richie was left in awe in February (14) when Britney Spears invited her on stage during her Las Vegas concert residency.

Lionel Richie's daughter has been a huge fan of the Toxic hitmaker since she was 15 and she couldn't contain her excitement when Spears summoned her to the platform as part of her Britney: Piece of Me show.

During the performance, Richie had a leash tied around her neck and was led around the stage on all fours by Spears.

She explains, "Britney Spears came out when I was 15 and this was the last time that I was like, a die-hard fan. You know when you're 15 and that person comes out and you just die for them? So that love never went away. When I see Britney Spears, I turn into my 15-year-old self, I can't even handle it.

"I finally go to see her in (Las) Vegas... and her big security guard taps me on the shoulder and says, 'Come with me.' I'm like, 'Ok...' I got walked on stage, Britney walked me like a dog, spanked me with a whip. It was the greatest moment of my life..."